565 lines
12 KiB
C
565 lines
12 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007 rPath, Inc. - All Rights Reserved
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*
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* ----------------------------------------------------------------------- */
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/*
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* Oh, it's a waste of space, but oh-so-yummy for debugging.
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*/
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#include <linux/stdarg.h>
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#include <linux/compiler.h>
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#include <linux/ctype.h>
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#include <linux/kernel.h>
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#include <linux/limits.h>
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#include <linux/string.h>
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#include <linux/types.h>
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static
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int skip_atoi(const char **s)
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{
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int i = 0;
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while (isdigit(**s))
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i = i * 10 + *((*s)++) - '0';
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return i;
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}
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/*
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* put_dec_full4 handles numbers in the range 0 <= r < 10000.
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* The multiplier 0xccd is round(2^15/10), and the approximation
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* r/10 == (r * 0xccd) >> 15 is exact for all r < 16389.
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*/
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static
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void put_dec_full4(char *end, unsigned int r)
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{
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int i;
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for (i = 0; i < 3; i++) {
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unsigned int q = (r * 0xccd) >> 15;
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*--end = '0' + (r - q * 10);
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r = q;
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}
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*--end = '0' + r;
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}
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/* put_dec is copied from lib/vsprintf.c with small modifications */
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/*
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* Call put_dec_full4 on x % 10000, return x / 10000.
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* The approximation x/10000 == (x * 0x346DC5D7) >> 43
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* holds for all x < 1,128,869,999. The largest value this
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* helper will ever be asked to convert is 1,125,520,955.
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* (second call in the put_dec code, assuming n is all-ones).
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*/
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static
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unsigned int put_dec_helper4(char *end, unsigned int x)
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{
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unsigned int q = (x * 0x346DC5D7ULL) >> 43;
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put_dec_full4(end, x - q * 10000);
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return q;
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}
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/* Based on code by Douglas W. Jones found at
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* <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
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* (with permission from the author).
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* Performs no 64-bit division and hence should be fast on 32-bit machines.
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*/
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static
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char *put_dec(char *end, unsigned long long n)
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{
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unsigned int d3, d2, d1, q, h;
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char *p = end;
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d1 = ((unsigned int)n >> 16); /* implicit "& 0xffff" */
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h = (n >> 32);
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d2 = (h ) & 0xffff;
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d3 = (h >> 16); /* implicit "& 0xffff" */
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/* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0
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= 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */
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q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((unsigned int)n & 0xffff);
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q = put_dec_helper4(p, q);
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p -= 4;
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q += 7671 * d3 + 9496 * d2 + 6 * d1;
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q = put_dec_helper4(p, q);
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p -= 4;
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q += 4749 * d3 + 42 * d2;
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q = put_dec_helper4(p, q);
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p -= 4;
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q += 281 * d3;
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q = put_dec_helper4(p, q);
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p -= 4;
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put_dec_full4(p, q);
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p -= 4;
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/* strip off the extra 0's we printed */
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while (p < end && *p == '0')
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++p;
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return p;
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}
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static
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char *number(char *end, unsigned long long num, int base, char locase)
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{
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/*
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* locase = 0 or 0x20. ORing digits or letters with 'locase'
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* produces same digits or (maybe lowercased) letters
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*/
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/* we are called with base 8, 10 or 16, only, thus don't need "G..." */
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static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
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switch (base) {
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case 10:
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if (num != 0)
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end = put_dec(end, num);
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break;
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case 8:
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for (; num != 0; num >>= 3)
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*--end = '0' + (num & 07);
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break;
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case 16:
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for (; num != 0; num >>= 4)
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*--end = digits[num & 0xf] | locase;
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break;
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default:
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unreachable();
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}
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return end;
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}
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#define ZEROPAD 1 /* pad with zero */
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#define SIGN 2 /* unsigned/signed long */
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#define PLUS 4 /* show plus */
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#define SPACE 8 /* space if plus */
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#define LEFT 16 /* left justified */
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#define SMALL 32 /* Must be 32 == 0x20 */
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#define SPECIAL 64 /* 0x */
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#define WIDE 128 /* UTF-16 string */
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static
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int get_flags(const char **fmt)
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{
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int flags = 0;
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do {
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switch (**fmt) {
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case '-':
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flags |= LEFT;
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break;
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case '+':
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flags |= PLUS;
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break;
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case ' ':
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flags |= SPACE;
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break;
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case '#':
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flags |= SPECIAL;
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break;
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case '0':
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flags |= ZEROPAD;
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break;
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default:
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return flags;
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}
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++(*fmt);
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} while (1);
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}
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static
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int get_int(const char **fmt, va_list *ap)
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{
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if (isdigit(**fmt))
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return skip_atoi(fmt);
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if (**fmt == '*') {
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++(*fmt);
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/* it's the next argument */
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return va_arg(*ap, int);
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}
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return 0;
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}
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static
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unsigned long long get_number(int sign, int qualifier, va_list *ap)
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{
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if (sign) {
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switch (qualifier) {
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case 'L':
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return va_arg(*ap, long long);
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case 'l':
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return va_arg(*ap, long);
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case 'h':
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return (short)va_arg(*ap, int);
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case 'H':
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return (signed char)va_arg(*ap, int);
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default:
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return va_arg(*ap, int);
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};
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} else {
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switch (qualifier) {
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case 'L':
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return va_arg(*ap, unsigned long long);
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case 'l':
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return va_arg(*ap, unsigned long);
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case 'h':
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return (unsigned short)va_arg(*ap, int);
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case 'H':
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return (unsigned char)va_arg(*ap, int);
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default:
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return va_arg(*ap, unsigned int);
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}
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}
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}
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static
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char get_sign(long long *num, int flags)
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{
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if (!(flags & SIGN))
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return 0;
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if (*num < 0) {
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*num = -(*num);
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return '-';
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}
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if (flags & PLUS)
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return '+';
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if (flags & SPACE)
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return ' ';
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return 0;
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}
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static
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size_t utf16s_utf8nlen(const u16 *s16, size_t maxlen)
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{
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size_t len, clen;
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for (len = 0; len < maxlen && *s16; len += clen) {
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u16 c0 = *s16++;
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/* First, get the length for a BMP character */
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clen = 1 + (c0 >= 0x80) + (c0 >= 0x800);
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if (len + clen > maxlen)
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break;
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/*
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* If this is a high surrogate, and we're already at maxlen, we
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* can't include the character if it's a valid surrogate pair.
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* Avoid accessing one extra word just to check if it's valid
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* or not.
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*/
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if ((c0 & 0xfc00) == 0xd800) {
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if (len + clen == maxlen)
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break;
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if ((*s16 & 0xfc00) == 0xdc00) {
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++s16;
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++clen;
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}
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}
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}
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return len;
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}
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static
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u32 utf16_to_utf32(const u16 **s16)
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{
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u16 c0, c1;
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c0 = *(*s16)++;
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/* not a surrogate */
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if ((c0 & 0xf800) != 0xd800)
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return c0;
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/* invalid: low surrogate instead of high */
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if (c0 & 0x0400)
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return 0xfffd;
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c1 = **s16;
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/* invalid: missing low surrogate */
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if ((c1 & 0xfc00) != 0xdc00)
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return 0xfffd;
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/* valid surrogate pair */
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++(*s16);
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return (0x10000 - (0xd800 << 10) - 0xdc00) + (c0 << 10) + c1;
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}
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#define PUTC(c) \
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do { \
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if (pos < size) \
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buf[pos] = (c); \
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++pos; \
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} while (0);
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int vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
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{
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/* The maximum space required is to print a 64-bit number in octal */
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char tmp[(sizeof(unsigned long long) * 8 + 2) / 3];
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char *tmp_end = &tmp[ARRAY_SIZE(tmp)];
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long long num;
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int base;
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const char *s;
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size_t len, pos;
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char sign;
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int flags; /* flags to number() */
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int field_width; /* width of output field */
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int precision; /* min. # of digits for integers; max
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number of chars for from string */
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int qualifier; /* 'h', 'hh', 'l' or 'll' for integer fields */
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va_list args;
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/*
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* We want to pass our input va_list to helper functions by reference,
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* but there's an annoying edge case. If va_list was originally passed
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* to us by value, we could just pass &ap down to the helpers. This is
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* the case on, for example, X86_32.
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* However, on X86_64 (and possibly others), va_list is actually a
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* size-1 array containing a structure. Our function parameter ap has
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* decayed from T[1] to T*, and &ap has type T** rather than T(*)[1],
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* which is what will be expected by a function taking a va_list *
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* parameter.
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* One standard way to solve this mess is by creating a copy in a local
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* variable of type va_list and then passing a pointer to that local
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* copy instead, which is what we do here.
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*/
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va_copy(args, ap);
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for (pos = 0; *fmt; ++fmt) {
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if (*fmt != '%' || *++fmt == '%') {
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PUTC(*fmt);
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continue;
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}
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/* process flags */
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flags = get_flags(&fmt);
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/* get field width */
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field_width = get_int(&fmt, &args);
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if (field_width < 0) {
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field_width = -field_width;
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flags |= LEFT;
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}
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if (flags & LEFT)
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flags &= ~ZEROPAD;
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/* get the precision */
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precision = -1;
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if (*fmt == '.') {
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++fmt;
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precision = get_int(&fmt, &args);
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if (precision >= 0)
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flags &= ~ZEROPAD;
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}
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/* get the conversion qualifier */
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qualifier = -1;
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if (*fmt == 'h' || *fmt == 'l') {
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qualifier = *fmt;
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++fmt;
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if (qualifier == *fmt) {
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qualifier -= 'a'-'A';
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++fmt;
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}
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}
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sign = 0;
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switch (*fmt) {
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case 'c':
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flags &= LEFT;
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s = tmp;
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if (qualifier == 'l') {
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((u16 *)tmp)[0] = (u16)va_arg(args, unsigned int);
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((u16 *)tmp)[1] = L'\0';
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precision = INT_MAX;
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goto wstring;
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} else {
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tmp[0] = (unsigned char)va_arg(args, int);
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precision = len = 1;
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}
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goto output;
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case 's':
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flags &= LEFT;
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if (precision < 0)
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precision = INT_MAX;
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|
s = va_arg(args, void *);
|
||
|
|
if (!s)
|
||
|
|
s = precision < 6 ? "" : "(null)";
|
||
|
|
else if (qualifier == 'l') {
|
||
|
|
wstring:
|
||
|
|
flags |= WIDE;
|
||
|
|
precision = len = utf16s_utf8nlen((const u16 *)s, precision);
|
||
|
|
goto output;
|
||
|
|
}
|
||
|
|
precision = len = strnlen(s, precision);
|
||
|
|
goto output;
|
||
|
|
|
||
|
|
/* integer number formats - set up the flags and "break" */
|
||
|
|
case 'o':
|
||
|
|
base = 8;
|
||
|
|
break;
|
||
|
|
|
||
|
|
case 'p':
|
||
|
|
if (precision < 0)
|
||
|
|
precision = 2 * sizeof(void *);
|
||
|
|
fallthrough;
|
||
|
|
case 'x':
|
||
|
|
flags |= SMALL;
|
||
|
|
fallthrough;
|
||
|
|
case 'X':
|
||
|
|
base = 16;
|
||
|
|
break;
|
||
|
|
|
||
|
|
case 'd':
|
||
|
|
case 'i':
|
||
|
|
flags |= SIGN;
|
||
|
|
fallthrough;
|
||
|
|
case 'u':
|
||
|
|
flags &= ~SPECIAL;
|
||
|
|
base = 10;
|
||
|
|
break;
|
||
|
|
|
||
|
|
default:
|
||
|
|
/*
|
||
|
|
* Bail out if the conversion specifier is invalid.
|
||
|
|
* There's probably a typo in the format string and the
|
||
|
|
* remaining specifiers are unlikely to match up with
|
||
|
|
* the arguments.
|
||
|
|
*/
|
||
|
|
goto fail;
|
||
|
|
}
|
||
|
|
if (*fmt == 'p') {
|
||
|
|
num = (unsigned long)va_arg(args, void *);
|
||
|
|
} else {
|
||
|
|
num = get_number(flags & SIGN, qualifier, &args);
|
||
|
|
}
|
||
|
|
|
||
|
|
sign = get_sign(&num, flags);
|
||
|
|
if (sign)
|
||
|
|
--field_width;
|
||
|
|
|
||
|
|
s = number(tmp_end, num, base, flags & SMALL);
|
||
|
|
len = tmp_end - s;
|
||
|
|
/* default precision is 1 */
|
||
|
|
if (precision < 0)
|
||
|
|
precision = 1;
|
||
|
|
/* precision is minimum number of digits to print */
|
||
|
|
if (precision < len)
|
||
|
|
precision = len;
|
||
|
|
if (flags & SPECIAL) {
|
||
|
|
/*
|
||
|
|
* For octal, a leading 0 is printed only if necessary,
|
||
|
|
* i.e. if it's not already there because of the
|
||
|
|
* precision.
|
||
|
|
*/
|
||
|
|
if (base == 8 && precision == len)
|
||
|
|
++precision;
|
||
|
|
/*
|
||
|
|
* For hexadecimal, the leading 0x is skipped if the
|
||
|
|
* output is empty, i.e. both the number and the
|
||
|
|
* precision are 0.
|
||
|
|
*/
|
||
|
|
if (base == 16 && precision > 0)
|
||
|
|
field_width -= 2;
|
||
|
|
else
|
||
|
|
flags &= ~SPECIAL;
|
||
|
|
}
|
||
|
|
/*
|
||
|
|
* For zero padding, increase the precision to fill the field
|
||
|
|
* width.
|
||
|
|
*/
|
||
|
|
if ((flags & ZEROPAD) && field_width > precision)
|
||
|
|
precision = field_width;
|
||
|
|
|
||
|
|
output:
|
||
|
|
/* Calculate the padding necessary */
|
||
|
|
field_width -= precision;
|
||
|
|
/* Leading padding with ' ' */
|
||
|
|
if (!(flags & LEFT))
|
||
|
|
while (field_width-- > 0)
|
||
|
|
PUTC(' ');
|
||
|
|
/* sign */
|
||
|
|
if (sign)
|
||
|
|
PUTC(sign);
|
||
|
|
/* 0x/0X for hexadecimal */
|
||
|
|
if (flags & SPECIAL) {
|
||
|
|
PUTC('0');
|
||
|
|
PUTC( 'X' | (flags & SMALL));
|
||
|
|
}
|
||
|
|
/* Zero padding and excess precision */
|
||
|
|
while (precision-- > len)
|
||
|
|
PUTC('0');
|
||
|
|
/* Actual output */
|
||
|
|
if (flags & WIDE) {
|
||
|
|
const u16 *ws = (const u16 *)s;
|
||
|
|
|
||
|
|
while (len-- > 0) {
|
||
|
|
u32 c32 = utf16_to_utf32(&ws);
|
||
|
|
u8 *s8;
|
||
|
|
size_t clen;
|
||
|
|
|
||
|
|
if (c32 < 0x80) {
|
||
|
|
PUTC(c32);
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Number of trailing octets */
|
||
|
|
clen = 1 + (c32 >= 0x800) + (c32 >= 0x10000);
|
||
|
|
|
||
|
|
len -= clen;
|
||
|
|
s8 = (u8 *)&buf[pos];
|
||
|
|
|
||
|
|
/* Avoid writing partial character */
|
||
|
|
PUTC('\0');
|
||
|
|
pos += clen;
|
||
|
|
if (pos >= size)
|
||
|
|
continue;
|
||
|
|
|
||
|
|
/* Set high bits of leading octet */
|
||
|
|
*s8 = (0xf00 >> 1) >> clen;
|
||
|
|
/* Write trailing octets in reverse order */
|
||
|
|
for (s8 += clen; clen; --clen, c32 >>= 6)
|
||
|
|
*s8-- = 0x80 | (c32 & 0x3f);
|
||
|
|
/* Set low bits of leading octet */
|
||
|
|
*s8 |= c32;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
while (len-- > 0)
|
||
|
|
PUTC(*s++);
|
||
|
|
}
|
||
|
|
/* Trailing padding with ' ' */
|
||
|
|
while (field_width-- > 0)
|
||
|
|
PUTC(' ');
|
||
|
|
}
|
||
|
|
fail:
|
||
|
|
va_end(args);
|
||
|
|
|
||
|
|
if (size)
|
||
|
|
buf[min(pos, size-1)] = '\0';
|
||
|
|
|
||
|
|
return pos;
|
||
|
|
}
|
||
|
|
|
||
|
|
int snprintf(char *buf, size_t size, const char *fmt, ...)
|
||
|
|
{
|
||
|
|
va_list args;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
va_start(args, fmt);
|
||
|
|
i = vsnprintf(buf, size, fmt, args);
|
||
|
|
va_end(args);
|
||
|
|
return i;
|
||
|
|
}
|